NEW YORK – On a day when they lose starter Andy Pettite for two weeks, the Yankees appeared to avoid another calamity when catcher Chris Stewart received a clean MRI on his left groin. Stewart “felt a grab” while running the bases on Thursday, he said. But no injury could be found.

He’ll rest for a few days, with Austin Romine as the starter. Stewart is available as a backup.

“The best thing is just to not irritate it,” he said before Friday’s 5-0 victory over Toronto. “Let it be for a couple days, and hopefully by the third or fourth day, I’ll be out there.”

Romine aced his first test as the temporary starter. He achieved an excellent rhythm with starter Hiroki Kuroda. He also contributed a pair of hits, including an RBI double. Romine attributed his success to a recent mechanical tweak with hitting coach Kevin Long. He added a leg kick to his swing.

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Reliever Joba Chamberlain (strained oblique) will throw a bullpen session on Sunday, Cashman said. Then the team will decide whether he can partake in another rehab assignment.

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Starter Ivan Nova (triceps inflammation) was not considered an option to replace Pettitte in the rotation, Cashman said. Though Nova’s right arm is healthy, he still must “just run him through the circuit first to make sure that everything he had was resolved” with the issue that caused him to be scratched from a big-league return earlier this week.

The exact nature of what caused Nova’s setback is murky. The initial reason given was trouble with his side. Girardi later corrected that to say the problem was located in his upper back. Cashman referred to a “ribcage” issue on Friday.